In a prior art method of making an integrally foam-molded seat, a seat trim cover is placed inside a mold to extend along the internal contour of the molding cavity the mold, and a polyurethane resin solution is directly injected onto the trim cover in the mold to make the desired integrally foam-molded seat. However, the prior art method has the following defects:
(A) It is difficult to accurately position the trim cover in the molding cavity of the mold. PA1 (B) When a defect such as a void is found in the molded polyurethane foam, its correction is not easy, and the man-hours and materials which were required to make the molded polyurethane foam are wasted, resulting in a great industrial loss. PA1 (C) Because the foaming pressure only is resorted to for molding the polyurethane foam integrally combined with the trim cover, the molded shape is not always accurate when the pressure is not sufficient.